How do I do criticise that the family maintain capitalism?

I'm assuming you're talking about the Marxist Perspective of the Nuclear Family? Some criticisms include:
1) The theory is too deterministic – it assumes people passively accept socialisation and family life, and that the future is pre-determined.
2) It ignores family diversity in capitalist society, and that many women now work full time as well
3) Feminists argue that the Marxist focus on class ignores the inequalities between men and women, which is the real source of female oppression.
Marxism ignore the benefits of nuclear family e.g. both parents support the children